Portable electronic devices, such as radios, typically use an energy source in the form of a battery to derive power necessary for their operation. The battery can comprise a single battery cell or a plurality of battery cells arranged in a suitable fashion to provide a desired supply voltage. A contacting scheme is required to reliably connect the energy source with the external electronic device during all modes of operation.
An example of a more demanding mode is when the electronic device, such as a radio, has been dropped. Any movement of the battery during the shock and vibration created by the impact of the drop could cause a loss of power to the device due to breakage of battery connections. The loss of power to the device may have undesirable or even unpredictable effects on device operation. For example, in the case of a device which uses a volatile memory circuit, loss of power could amount to a total loss of memory. An important point which must be considered in the case of portable radios, is that the mass of the battery comprises a significant portion of the total mass of the radio. In this case, retaining the battery in a constant position in all possible orientations and under shocks and vibration becomes very important.
Battery cells are often cylindrically or rectangularly shaped and include positive and negative electrical contact surfaces at their opposed ends. Generally, a number of battery cells are serially coupled to produce a battery pack which is inserted into a cylindrical chamber or a rectangular chamber formed within a battery housing. To contact a battery, present embodiments require that conductive contacts be placed at opposite ends of the chamber so as to contact battery terminals. One of the conventional methods uses a conductive spring contact that compresses against the battery pack when it is positioned in the chamber. The spring force exerted by the spring contact acts to retain the battery against an opposing conductive contact. Alternatively, shock absorbing pads may be positioned at one of the opposing ends of the battery housing to prevent battery movements. However, in order to accommodate the spring contacts of the shock absorbing pad, these approaches increase the height of the battery package.
Another method for reducing battery movements is the application of hot melt after the battery pack is inserted into the battery housing. In this method, melted epoxy is deposited between the battery pack and the housing member to bond them to each other. When the epoxy is cured, the battery is secured to the battery housing. This process, however, is labor intensive and requires an elaborate process control mechanism to ensure adequate hot melt deposition. Excessive deposition may cause cosmetic defects and insufficient deposition may create a weak bond which increases the chance of breakage. Additionally, once the epoxy is cured, the battery pack becomes unsalvagable when the battery housing needs to be replaced.
Another method comprises positioning a pad having double-sided adhesive surfaces between the battery pack and the housing member. The pad effectively prevents movement by neutralizing the sheer forces exerted against the battery pack during shock or vibration by neutralizing the sheer forces exerted against. In this method, one adhesive side is attached to a battery housing wall while the other adhesive side is exposed and later attaches to the battery pack. This approach is desired in assembling battery packages which do not require inserting the battery in a chamber-like housing. However, in a battery housing which includes a chamber or pocket, the exposed adhesive surface makes insertion of the battery pack extremely difficult. This is because the exposed adhesive surface presents a resistive force against the battery pack during insertion.
Therefore, it is desired to provide an adhesive pad for preventing device movement which allows easy insertion of the device into a chamber-like housing.